The invention relates to an actuator for a motor vehicle, more specifically for a motor vehicle seat, with an electric motor having an output shaft, with a transmission comprising a worm, a spindle nut and a spindle, said worm being rotationally joined to said output shaft, said spindle nut comprising a worm gear that engages said worm and also a spindle thread that engages said spindle, said worm having a worm axis and said spindle nut having a spindle nut axis as well as to a longitudinal adjustment device equipped with such an actuator. Such type actuators have been known from WO 03/068551 A1, U.S. Pat. Nos. 5,924,668 A, 5,860,319 A and 6,260,922 B1.
The worm axes thereby extend at an angle of 90° or at an angle of 0° to the longitudinal direction of the spindle, the longitudinal direction of the spindle coinciding with the axis of the spindle nut. Usually, the electric motor is connected through a bendable shaft to the transmission, meaning to the worm. It has been found out that, in operation, this bendable shaft may generate noises which in most cases do not occur permanently but under certain strains, possibly already in the event of an adjustment in one direction. Such type noises are disadvantageous. Many attempts have been made to minimize or dampen these noises.
Many actuators, for example the one according to U.S. Pat. No. 6,260,922 B1, have the electric motor located on a line joining the worms of the two pairs of rails. The bendable shaft extends more or less on a straight line. The electric motor is thereby located on the motor vehicle seat at a place offering little space, namely substantially directly underneath a passenger's buttocks. If it is wanted to accommodate the passenger as deep as possible inside the motor vehicle, there is too little space left for an electric motor beneath his buttocks; in the x direction toward the front, for example beneath the thighs, there is space available, though.
This is where the invention comes into play. It is an object of the invention to dispose the electric motor farther front with respect to the deepest point of the seat in the x direction so that the general structure height may be reduced, meaning so that the passenger may be disposed in closer proximity to an undercarriage of the motor vehicle than hitherto possible.